cvedb.io
CVE-2026-31669
CRITICAL · CVSS 9.8
EPSS exploitation probability: 0%
Published 2026-04-24T15:16:46.663 · Last modified 2026-06-17T10:34:12.197

Summary

In the Linux kernel, the following vulnerability has been resolved: mptcp: fix slab-use-after-free in __inet_lookup_established The ehash table lookups are lockless and rely on SLAB_TYPESAFE_BY_RCU to guarantee socket memory stability during RCU read-side critical sections. Both tcp_prot and tcpv6_prot have their slab caches created with this flag via proto_register(). However, MPTCP's mptcp_subflow_init() copies tcpv6_prot into tcpv6_prot_override during inet_init() (fs_initcall, level 5), before inet6_init() (module_init/device_initcall, level 6) has called proto_register(&tcpv6_prot). At that point, tcpv6_prot.slab is still NULL, so tcpv6_prot_override.slab remains NULL permanently. This causes MPTCP v6 subflow child sockets to be allocated via kmalloc (falling into kmalloc-4k) inst

Affected products

linux — linux_kernel

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.